How to split a matrix columnwise and save each part as a matrix_part_i.txt file using a loop?

I want to split a matrix column-wise and

save each part with correct index.

The begin and end of each part is determined by a

parameter p as coded below:

clear;

X=rand(5,10); %Let M be a matrix with 10 columns

NUMBER_OF_OUTPUT_PARTS=2; %Let 2 be the amount of parts of a matrix

TOTAL_NUMBER_OF_COLUMNS=size(X,2);

NUMBER_OF_COLUMNS_PER_PART=TOTAL_NUMBER_OF_COLUMNS/NUMBER_OF_OUTPUT_P

ARTS;

for p=1:NUMBER_OF_OUTPUT_PARTS;

      Xp{p}=X(:,

((p-1)*NUMBER_OF_COLUMNS_PER_PART)+1:NUMBER_OF_COLUMNS_PER_PART*p); 

%Partition of main matrix into 2 parts

end;

%Output is two matrices each with 5 columns, as expected!!!

Since A=Xp{1,1} gives the first part

and B=Mp{1,2} the second part and so on,

I thought that I could automatically save all parts within the same

code by writing the following lines within the loop:

Xp{p}=X(:,

((p-1)*NUMBER_OF_COLUMNS_PER_PART)+1:NUMBER_OF_COLUMNS_PER_PART*p);

fid = fopen('Xp{p}.txt', 'wt');

fprintf(fid, [repmat('%g\t', 1, size(Xp{p},2)-1) '%g\n'], Xp{p}.');

fclose(fid);

Unfortunately it did not work.

So I wounder if someone knows what I should do to extract each part

of main matrix and save automatically within the loop with the

correct index without overwriting.

Thank you in advance for your help

Emerson

[Oleg Komarov]

Please read this tutorial: http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

Answer 1

[Walter Roberson]

You would probably find it easier to use mat2cell() to split the matrix.

In your line

fid = fopen('Xp{p}.txt', 'wt');

you are using the same output file name each time. Perhaps you want something like,

fid = fopen(sprintf('X_%d.txt',p),'wt');

[Emerson De Souza]

Thank you Walter,

your suggested line solved the problem.

Later I will try the advantages of using mat2cell() to split the matrix and compare with the current commands.

I wish you a nice weekend

Emerson